Model GPS receiver. Uses trilateration to compute location given satellite data. Location and time data are given in the following format:

<time> <latitude minutes> <latitude degrees> <latitude seconds> <northern/southern hemisphere> <longitude minutes> <longitude degrees> <longitude seconds> <eastern/western hemisphere> <elevation>

The (Java) vehicle uses vehicle.class and angles.class. To compile satellite and receiver programs, run

gcc gps.c receiver.c matops.c cholSolve.c getSatellite.c -o receiver
gcc gps.c satellite.c matops.c cholSolve.c getSatellite.c -o satellite

gps.c contains helper functions for the satellite and receiver while matops.c and cholSolve contain linear algebra operations. Linear algebra files can be found in nla repository. As an example, the following shows location data for a trip from Salt Lake City to the point of zero latitude and longitude:

$ cat o.dat | java vehicle 
102123.21 40 45 55.0 1 111 50 58.0 -1 1372.0
103220.63 36 14 8.88 1 99 25 18.22 -1 1219.55
104318.05 31 42 22.77 1 86 59 38.44 -1 1067.11
105415.47 27 10 36.66 1 74 33 58.66 -1 914.66
106512.89 22 38 50.55 1 62 8 18.88 -1 762.22
107610.31 18 7 4.44 1 49 42 39.11 -1 609.77
108707.73 13 35 18.33 1 37 16 59.33 -1 457.33
109805.15 9 3 32.22 1 24 51 19.55 -1 304.88
110902.57 4 31 46.11 1 12 25 39.77 -1 152.44
112000.0 0 0 0.0 1 0 0 0.0 1 0.0

To run the satellite and receiver programs, pipe the vehicle data to the satellite then to the receiver:

$ cat o.dat | java vehicle | ./satellite | ./receiver
102123.210000 40 45 55.000155 1 111 50 58.000095 -1 1371.999970
103220.630000 36 14 8.880108 1 99 25 18.220047 -1 1219.548082
104318.050000 31 42 22.769938 1 86 59 38.439948 -1 1067.111167
105415.470000 27 10 36.659983 1 74 33 58.659937 -1 914.660985
106512.890000 22 38 50.550094 1 62 8 18.880087 -1 762.217440
107610.310000 18 7 4.440011 1 49 42 39.109978 -1 609.770477
108707.730000 13 35 18.330040 1 37 16 59.330011 -1 457.326804
109805.150000 9 3 32.220014 1 24 51 19.550042 -1 304.877032
110902.570000 4 31 46.109995 1 12 25 39.770018 -1 152.441257
112000.000000 0 0 0.000032 1 0 0 0.000038 -1 0.000163

This should approximate the location data given by the vehicle as in the previous line.